금강경 한역제본에 대한 연구

이건준 보조사상연구원 1998 九山論集 Vol.2 No.-

무선 Lan용 전압제어 Hair-Pin 공진 발진기 설계 및 제작 ( Design and Implementation of Voltage Controlled Hair-Pin Resonator Oscillator for Wireless LAN )

이건준,김대웅,하성재,홍의석 한국통신학회 1998 한국통신학회 학술대회논문집 Vol.21 No.2

Photoluminescence and Nonlinear Optical Properties of Semiconductor Nanocomposites Consisting of ZnO Nanorods and CdS Nanodots

이건준,이영백,임현진,정현식,길병호,한성환 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.51

In this research, we investigated the microstructures, the photoluminescence (PL) and the nonlinear optical properties of semiconductor nanocomposites consisting of ZnO nanorods and CdS nanodots. The ZnO nanorods and the CdS nanodot-adsorbed ZnO nanorods were grown in an aqueous solution of Zn(NO_3)_2 and hexamethyltetramine (HMT) by using chemical bath deposition. The room-temperature PL spectra under 325-nm continuous wave excitation showed an UV emission band with a peak at 3.25 eV and a band width of 160 meV, while the PL spectra at a low temperature of 10 K exhibited multiple bands with enhanced PL intensities. These results are thought to be related to the near-band-edge emission that originates from exciton transitions. From femtosecond Z-scan measurements at a wavelength of 800 nm, the ZnO nanorods exhibit nonlinear absorption due to three-photon absorption, and the CdS nanodot-adsorbed ZnO nanorods show the saturable absorption due to the exciton bleaching effect of the CdS nanodots.

Photoluminescence and Lasing Properties of ZnO Nanorods

이건준,이영백,임환홍,차명식,Sung Soo Kim,정현식,민선기,한성환 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.61

In this study, we investigated the structures, photoluminescence (PL), and lasing characteristics of the ZnO nanorods prepared by using chemical bath deposition. The continuous-wave HeCd laserexcited PL spectra of the ZnO nanorods exhibited two emission bands, one in the UV region and the other in the visible region. The UV emission band has its peak at 3.25 eV with a bandwidth of 160 meV. However, the PL spectra under 355-nm, 35-ps pulse excitation exhibited a spectrally-narrowed UV emission band with a peak at 3.20 eV and a spectral width of 35 meV. The lasing phenomena were ascribed to the amplified spontaneous emission (ASE) caused by coupling of the microcavity effect of ZnO nanorods and the high-intensity excitation. Above the lasing threshold, the ASE peak intensity exhibited a superlinear dependence on the excitation intensity. For an excitation pulse energy of 3 mJ, the ASE peak intensity was increased by enlarging the length of the ZnO nanorods from 1 µm to 4 µm. In addition, the PL spectrum under 800-nm femtosecond pulse excitation exhibited second harmonic generation, as well as the multiphoton absorption-induced UV emission band. In this research, ZnO nanorods were grown on seed layers by using chemical bath deposition in an aqueous solution of Zn(NO3)2 and hexamethyltetramine. The seed layers were prepared on conducting glass substrates by dip coating in an aqueous colloidal dispersion containing 50% 70-nm ZnO nanoparticles. Scanning electron microscopy clearly revealed that ZnO nanorods were successfully grown on the seed layers.

Inactivation of Escherichia coli, Saccharomyces cerevisiae, and Lactobacillus brevis in Low-fat Milk by Pulsed Electric Field Treatment: A Pilot-scale Study

이건준,한복궁,최혁준,강신호,백승천,이동운 한국축산식품학회 2015 한국축산식품학회지 Vol.35 No.6

We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 µs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorgan- isms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (p<0.05). These results indicate that a relatively low electric-field strength of 10 kV/cm can be used to pasteurize low-fat milk.

Femtosecond Laser Surface Structuring of Amorphous and Crystalline Silicon

이건준,오차환,윤종승,김은규,정현식,장진,손용덕,이영백 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.6

The surface structuring of amorphous and crystalline silicon was performed by using femtosecondlaser- induced phase transformations: i) amorphous-to-crystalline and ii) crystalline-to-amorphous. The amorphous silicon (a-Si) films were prepared on glass substrates by using plasma-enhanced chemical-vapor deposition. Two kinds of micropatterns were produced in the a-Si films: i) a twodimensional (2D) pattern (a word ‘q-Psi’) was produced by using the inverse Fourier transform of a computer-generated hologram, and ii) laser-induced gratings (LIGs) were made by means of two-beam interference of near-infrared femtosecond-laser pulses. By using micro-Raman spectroscopy, optical microscopy, scanning electron microscopy, and transmission electron microscopy, the femtosecond-laser pulses were found to induce a localized phase transformation from the amorphous to the crystalline phase, and the spatially-selected crystallization of a-Si was found to be responsible for the formation of patterns such as the LIG and the 2D pattern. Crystalline silicon (c-Si) with a SiO2 capping layer was also periodically modified by femtosecond holography. A micro- Raman study indicated that the LIG formation in c-Si could be ascribed to the spatially-selected amorphization of c-Si. The surface structuring of amorphous and crystalline silicon was performed by using femtosecondlaser-induced phase transformations: i) amorphous-to-crystalline and ii) crystalline-to-amorphous. The amorphous silicon (a-Si) films were prepared on glass substrates by using plasma-enhanced chemical-vapor deposition. Two kinds of micropatterns were produced in the a-Si films: i) a twodimensional (2D) pattern (a word ‘q-Psi’) was produced by using the inverse Fourier transform of a computer-generated hologram, and ii) laser-induced gratings (LIGs) were made by means of two-beam interference of near-infrared femtosecond-laser pulses. By using micro-Raman spectroscopy, optical microscopy, scanning electron microscopy, and transmission electron microscopy, the femtosecond-laser pulses were found to induce a localized phase transformation from the amorphous to the crystalline phase, and the spatially-selected crystallization of a-Si was found to be responsible for the formation of patterns such as the LIG and the 2D pattern. Crystalline silicon (c-Si) with a SiO2 capping layer was also periodically modified by femtosecond holography. A microRaman study indicated that the LIG formation in c-Si could be ascribed to the spatially-selected amorphization of c-Si.

Optical and Biological Properties of Plasma-Treated Neurospora crassa Spores as Studied by Absorption, Circular Dichroism, and Raman Spectroscopy

이건준,박경순,최은하 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.71 No.10

We studied the effect of plasma treatment on the optical, structural and biological properties of Neurospora crassa (N. crassa) spores. An atmospheric-pressure plasma jet (APPJ) was used to generate reactive oxygen and nitrogen species in aqueous solution. The APPJ treatment of N. crassa spores in water significantly reduced the viability of spores. The reduction in the spore viability can be attributed to the reactive species from the plasma itself and those derived from the reaction of plasma radicals with aqueous solution. These structural modifications were contingent on the medium in which N. crassa spores were suspended; plasma treatment of N. crassa spores in PBS did not significantly affect the viability of spores as compared with N. crassa spores in water. Scanning electron microscopy images and circular dichroism spectra indicated that the spore cell wall was damaged by plasma treatment. The optical absorption spectrum of untreated N. crassa spores exhibited two resonance absorption bands at approximately 1 ' 260 nm and 2 ' 472 nm, originating from deoxyribonucleic acid (DNA) and -carotene. The Raman spectrum of untreated N. crassa spores exhibited three main peaks at 1519, 1157 and 1006 cm−1, attributed to -carotene inside the cell wall. The Raman spectra showed that the APPJ treatment of N. crassa spores in water caused degradation of -carotene, affecting the viability of spores.

Correlation Between Microstructural and Optical-Diffraction Properties in Femtosecond-Laser-Induced Gratings of Amorphous Co2MnSi Film

이건준,윤종승,김전,김정훈,이영백 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.48 No.6

We studied the correlation between the microstructures and the optical diffraction properties in femtosecond-laser-induced gratings of an amorphous Co2MnSi (a-Co2MnSi) film. The a-Co2MnSi thin film was deposited on a glass substrate by using magnetron sputtering, and the crystallization of the a-Co2MnSi film was performed using two-beam interference of near-infrared femtosecondlaser pulses. For the femtosecond-laser-interference crystallization using two 120-μJ laser beams, the diffraction intensity slowly increased with the laser shot count until it reached a maximum intensity around 25900 laser shots; then, the diffraction intensity gradually decreased. From the cross-sectional and the plan-view transmission-electron-microscopy images of the laser-crystallized Co2MnSi regions, the crystallization reached deeper into the sample film under an optimized fluence condition. Meanwhile, a lower fluence beam resulted in a partially crystallized film, and a higher fluence beam made a partially damaged film. The femtosecond-laser-induced gratings consisted of alternating semicrystalline-Co2MnSi and polycrystalline-Co2MnSi bands with a period of about 2-μm.

범본 금강경류의 판본에 대한 연구

이건준 보조사상연구원 2000 九山論集 Vol.4 No.-

플레이트 거더의 수평보강재 필요 강성에 관한 해석적 연구

이건준,박용명,김병준,박찬희,Lee, Kun Joon,Park, Yong Myung,Kim, Byeong Jun,Park, Chan Hee 한국강구조학회 2016 韓國鋼構造學會 論文集 Vol.28 No.1

본 연구에서는 판 형상의 수평보강재가 한쪽에만 설치되는 통상적인 보강 웨브에서 수평보강재의 필요 강성에 대한 해석적 연구를 수행하였다. 실제 교량용 플레이트 거더는 대부분 비대칭 단면이지만 제작성을 감안하여 수평보강재를 통상 웨브 높이의 1/5인 0.2D 부근에 설치하고 있다. 이러한 점을 감안하여 보강재가 0.16D~0.24D 범위에 설치되는 조건에 대해 단면의 비대칭성과 웨브의 형상비를 고려하여 수평보강재의 강성비(${\gamma}^*$)에 따른 고유치 해석을 수행하고 좌굴강도를 평가하였다. 이로부터 AASHTO LRFD 기준의 좌굴강도를 만족하는 수평보강재의 필요 강성을 제안하였다. A numerical study on required stiffness of the longitudinal stiffener in the webs stiffened with flat plate at one-side of the web was conducted. The longitudinal stiffeners are commonly placed around 0.2D, i.e., 1/5 the web depth due to fabrication convenience although most plate girders for bridges are unsymmetric section. Considering asymmetry of section, aspect ratio of web and the rigidity ratio of longitudinal stiffener(${\gamma}^*$), eigenvalue analysis were performed to evaluate the buckling strength for the webs with a stiffener located at 0.16D~0.24D. Based on the parametric analysis, the required stiffness of the longitudinal stiffener to satisfy the buckling strength specified in AASHTO LRFD specifications was presented.